Lion invisible ink playing cards

Lion playing cards, jumbo index plastic cards single deck, red and blue are available.
How to check the good quality marked cards and normal quality marked poker cards?
There is a very easy way, different price, different quality.
It is the law of eternity.
However, we also have the other useful way to distinguish the quality cards.
Regardless of whatever marked playing cards are, all can work. It’s undetectable to the human eye unless you view it through a special infrared contact lenses.
In the old days, the most common invisible ink marking systems were ultraviolet (UV) invisible ink marked deck. UV chemicals were used that could only be viewed with UV contact lenses or marked cards glasses.
If we suspected someone was marking cards, we simply waved the light over them and we can see the marks. It is equal to uv invisible ink contact lenses and glasses that see through cards.
But that was so ’80s and ’90s. Nowadays, luminous marked cards are exploring new high-tech card marking systems. The method that is hot right now is infrared (IR) card marking. Without getting too scientific, IR contact lenses marked cards basically work better because a UV light will not detect the invisible ink playing cards.